1. Field of the Invention
The present invention relates to an image capturing apparatus, and more particularly to an image capturing apparatus with a movement compensation function and its movement compensation method to prevent any blurred image caused by involuntary hand movements.
2. Description of Related Art
As digital camera technology advances, more attention is paid to the technology for correcting blurred images caused by movement of the camera. The present digital camera stabilization technology is basically divided into two categories, respectively: an optical sensing mechanism and a software compensation mechanism to compensate for involuntary hand movements.
The principle of the optical sensing mechanism mainly utilizes a camera lens and a charge coupled device for its processing, and the sensing result of a motion sensor is used to control the module of camera lens or charge coupled device to compensate the movements of the camera. For the control of camera lens, the principle of a floating lens is adopted and a motion sensor is provided for detecting any movement or deviation. After a movement correction element calculates the deviation, the camera lens is driven to correct the optical axis and maintain a stable viewing screen. This advantage helps users to take sharp pictures. However, the stabilization effect is not significant (because the lens does not have sufficient space for its movement.) For the control of charge coupled device, similarly, a motion sensor is provided for detecting any movement or deviation, and a mechanical stand floating principle is adopted to adjust and correct the position of the charge coupled device to offset the blur of an image caused by camera movements. This stabilization effect is better than the effect by controlling the camera lens, but this design can give a lower quality of pictures only. Furthermore, this kind of stabilization mechanism must work together with a charge coupled device having a higher pixel resolution in practical applications, or else the picture may have blurs and poor quality even though it can provide a stable screen.
However, the stabilization technology of the aforementioned optical sensing mechanism comes with a complicated mechanism and incurs a high price, and thus such technology is generally applied in high-end cameras. For low-end light and thin cameras, the optical sensing mechanism obviously is not suitable for the low-end cameras in considering the mechanism and cost, and thus a common software compensating mechanism (commonly known as electronic image stabilization) is introduced.
The principle of the software compensating mechanism primarily uses a motion sensor to record the movement or vibration of a camera during the photographing process and provide information for recovering the image, which constitutes a post-processing technique for a single image captured by the camera. However, the general post-processing technique for a single image creates different image recovering qualities by different degrees of movements. Furthermore, the image recovering quality is affected by noise, and thus the actual final effect is not good enough, and blurred images and noise cannot be overcome easily for an optimization.